[FFmpeg-devel] Serious Regression in matroskaenc:

Soft Works softworkz at hotmail.com
Fri Dec 23 13:19:06 EET 2016

Hello everybody,

it's been a while since my contribution to matroskaenc in July. In case you don't remember my scenario - it's about realtime transcoding and and streaming of mkv files.
That means that the header is sent to the client before the ffmpeg process is completed.

In this context we discovered that the preliminary mkv header that is written initially is corrupted in some way!

When transcoding is aborted or completed, the header is written a second time, overwriting a few things. This final header write operation always fixes the problem and leaves the file with a correct header.

I haven't investigated yet, what's actually being written wrong. I used different parsing implementations (mediainfo, ffprobe, mkvvalidator, mkvtoolnix) and all are producing different results. Some report CRC error, others report unknown or duplicate header elements. Some are able to detect the stream information others are not. 

Now, I'm wondering if one of you guys could take care of this? Or do I have to find the bug on my own?

Best regards,


More information about the ffmpeg-devel mailing list